Illustration by Andrew Fazekas, SkySafari
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Saturn, Mars, and the star Antares will line up in the sky on Tuesday and Wednesday.

Illustration by Andrew Fazekas, SkySafari

This Week’s Night Sky: The Bull’s-Eye Winks Out and Worlds Align

Star clusters and a close planetary encounter will be visible this week.

Stellar Lineup After sunset on Tuesday and Wednesday (August 23 and 24), look for a stunning lineup of three brilliant bodies—Saturn, Mars, and Antares—above the southwest horizon.

The three have been arranged in a triangle for weeks but have now moved to form a straight line, ending at the red giant star Antares in the constellation Scorpius.

Backyard telescopes will offer an up-close look at both of the planets in the line. Mars will appear as a small orange-hued disk with a white polar cap and dark features dotting its surface, while Saturn’s rings, cloud belts, and largest moon Titan will all be clear to see. By Friday evening, Mars will appear to slide off to the south on a lonely path toward Sagittarius.

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After sunset on Tuesday, look for Saturn, Mars, and Antares in alignment in the southwest skies in the constellation Scorpius.

Bull’s-Eye Winks During the day on Thursday, August 25, the moon will appear to hide (or occult) the brilliant orange star Aldebaran. Using binoculars, viewers in the central and western United States can watch Aldebaran disappear behind the brighter part of the moon, then appear later along the unlit, dark portion of the moon’s disk. The earliest available viewing will be just after 5 a.m. in Hawaii, with sighting times coming later in areas farther to the east. For an exact listing of times for individual cities, consult this table from the International Occultation Timing Association.

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On Thursday during the daylight hours, look for the moon to occult the bright orange star Aldebaran, the eye of Taurus.

Cluster Under Foot In the predawn hours of Saturday, August 27, the moon will appear below the feet of the constellation Gemini, pointing the way to a beautiful nearby star cluster.

Known as Messier 35, the cluster consists of several hundred stars and measures about 24 light-years across. It’s visible to the naked eye, but binoculars will bring out the details of the grouping, even in a light-polluted suburban backyard. The cluster should easily appear in the same field of view as the moon, making it that much easier to locate.

The clustered stars are blue and white in color, which indicates they’re still fairly young—about 150 million years old. By comparison, our sun is estimated to be about 5 billion years old.

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In the predawn hours of Saturday, use the moon to hunt down the open star cluster Messier 35 in the Gemini constellation.

Venus-Jupiter Meet Up Sky-watchers across the globe are in for a great show at dusk on Saturday, August 27, as two of the brightest celestial objects will have a superclose encounter.

Venus and Jupiter will appear very low in the western sky, and they’ll seem to be quite close to each other, too. In the Americas, they’ll be just about 10 arc-minutes apart—that’s equal to only a third of the diameter of the moon’s disk.

Since this conjunction will be taking place so low to the horizon, the planets will be battling the glare of the twilight. Plan on using binoculars to make sure you get the best view of this special sky event. Stay tuned for a special viewer’s guide later this week.

Clear skies!

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After sunset on Saturday, look towards the very low western sky for a super-close conjunction between Venus and Jupiter.

Andrew Fazekas, the Night Sky Guy, is the author of Star Trek: The Official Guide to Our Universe. Follow him on Twitter, Facebook, and his website.

Tune in to National Geographic Facebook LIVE each Monday at 12:30 p.m. to see Andrew share the week’s best sky-watching sights and answer your questions about the night sky.